The invention relates to a varactor or mixer diode comprising a semiconductor element, which is in mesa shape and has a pn-junction, forming a rectifying layer, or a rectifying metal/semiconductor junction (Schottky contact) on the upper face of the mesa elevation, and has an ohmic substrate contact on the other side of the semiconductor element opposite the side on which the rectifying layer is to be found.
This type of semiconductor arrangement is known for example from 1976 IEEE International Solid-State Circuits Conf., pages 120/121, in which the semiconductor element is formed in mesa shape only in its region bordering the rectifying layer.
For applications for tuners, for example for VHF and UHF television tuners, high-quality variable capacitance diodes are required which have a fixed characteristic capacitance curve as a function of the applied voltage while having a large facility for varying the capacitance. In order to attain high Q-factors, the diode must have a very low series resistance. This series resistance essentially comprises the resistance of the epitaxial layer contained in the semiconductor arrangement and the spreading resistance. This spreading resistance is determined substantially by the skin effect.